export default function Base64(value: string, type: number = 1) {
	const base64 = new Base64Util()
	if (type === 1) {
		return base64.encode(value)
	} else {
		return base64.decode(value)
	}
}

function Base64Util() {
	// 私钥
	let _keyStr = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
	// 加密
	this.encode = function(input) {
		var output = ''
		var chr1, chr2, chr3, enc1, enc2, enc3, enc4
		var i = 0
		input = _utf8_encode(input)
		while (i < input.length) {
			chr1 = input.charCodeAt(i++)
			chr2 = input.charCodeAt(i++)
			chr3 = input.charCodeAt(i++)
			enc1 = chr1 >> 2
			enc2 = ((chr1 & 3) << 4) | (chr2 >> 4)
			enc3 = ((chr2 & 15) << 2) | (chr3 >> 6)
			enc4 = chr3 & 63
			if (isNaN(chr2)) {
				enc3 = enc4 = 64
			} else if (isNaN(chr3)) {
				enc4 = 64
			}
			output = output + _keyStr.charAt(enc1) + _keyStr.charAt(enc2) + _keyStr.charAt(enc3) + _keyStr.charAt(enc4)
		}
		return output
	}
	// 解密
	this.decode = input => {
		var output = ''
		var chr1, chr2, chr3
		var enc1, enc2, enc3, enc4
		var i = 0
		if (input == undefined || input == null) {
		} else {
			input = input.replace(/[^A-Za-z0-9\+\/\=]/g, '')
			while (i < input.length) {
				enc1 = _keyStr.indexOf(input.charAt(i++))
				enc2 = _keyStr.indexOf(input.charAt(i++))
				enc3 = _keyStr.indexOf(input.charAt(i++))
				enc4 = _keyStr.indexOf(input.charAt(i++))
				chr1 = (enc1 << 2) | (enc2 >> 4)
				chr2 = ((enc2 & 15) << 4) | (enc3 >> 2)
				chr3 = ((enc3 & 3) << 6) | enc4
				output = output + String.fromCharCode(chr1)
				if (enc3 != 64) {
					output = output + String.fromCharCode(chr2)
				}
				if (enc4 != 64) {
					output = output + String.fromCharCode(chr3)
				}
			}
			output = _utf8_decode(output)
			return output
		}
	}
	// private method for UTF-8 encoding
	let _utf8_encode = string => {
		string = string.replace(/\r\n/g, '\n')
		var utftext = ''
		for (var n = 0; n < string.length; n++) {
			var c = string.charCodeAt(n)
			if (c < 128) {
				utftext += String.fromCharCode(c)
			} else if (c > 127 && c < 2048) {
				utftext += String.fromCharCode((c >> 6) | 192)
				utftext += String.fromCharCode((c & 63) | 128)
			} else {
				utftext += String.fromCharCode((c >> 12) | 224)
				utftext += String.fromCharCode(((c >> 6) & 63) | 128)
				utftext += String.fromCharCode((c & 63) | 128)
			}
		}
		return utftext
	}
	// private method for UTF-8 decoding
	let _utf8_decode = utftext => {
		var string = ''
		var i = 0
		var c = (c1 = c2 = 0)
		var c1 = 0
		var c2 = 0
		var c3 = 0
		while (i < utftext.length) {
			c = utftext.charCodeAt(i)
			if (c < 128) {
				string += String.fromCharCode(c)
				i++
			} else if (c > 191 && c < 224) {
				c2 = utftext.charCodeAt(i + 1)
				string += String.fromCharCode(((c & 31) << 6) | (c2 & 63))
				i += 2
			} else {
				c2 = utftext.charCodeAt(i + 1)
				c3 = utftext.charCodeAt(i + 2)
				string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63))
				i += 3
			}
		}
		return string
	}
}
